The use of mechanistic data to link experimental and human results is justified when there is a specific and strong correspondence between the different systems such as presence of the same DNA damages and mutations in the same cancer-related genes in both human tumors, experimental animals and in vitro systems, as in the case of benzo[a]pyrene, alterations in TP53 gene, and lung cancer (IARC, 2010). The gene discussed is TP53; the disease is lung carcinoma.